Improvement in steam-gages



1. 1. DUCUMET; 2 Sheets-Sheet 1.

Steam Pressure Gage.

Patented Jany 9, 1866.

Y No. 52,006.

zsheets Sheen.

1.1. DUCOMET.

lSteam Pressure Gage.

W/T/Vfssfs N. PETERS. PholLilhognphcr. Washnan. D. C.

UNITED STATES PATENT OEEICEo J OAOHIM JOSEPH DUCOMET, OF PARIS, FRANCE.

IMPROVEM ENT IN STEAM-GASES.l

Specification forming part of Letters Patent No. 52,006, dated January 9, 1866.

Athese instruments a great sensitiveness, allowing them to work with constant and mathe- Inatical regularity, which to this day none of the instruments used for similar purposes has been able to do for any length of time. All ot' them, after working some time, give false and dangerous indications if they be relied on.

In the annexed drawings I have represented, in full size, myimproved steam-gage and several modifications, which may be introduced in its arrangements and ttings. The most important part of my steam-gage is a metallic caporsteam-receiver, A. (ShowninFignresl, 2, and 4.) This cap is entirely different from any other contrivance hitherto made for the same purpose. It is composed of a very thin copper or brass sheet rolled up many times between hard cylinders, then covered up with a silver sheet still thinner. This second sheet is also rolled up several times. These repeated rollin gs are for the purpose of tightening the particles of metal and give them, when together, great power ot' resistance and pliability in small thickness. The two sheets, being thus placed over one another, are heated to the degree of melting silver. They become closely united together and form a single sheet. When in this state the compound sheet is again rolled up before it is submitted to the following operation. It is obvious that the metallic sheet thus obtained must be very dense, and besides its thickness, brought down to one-fortieth or one-tittieth ot'an inch, becomes very pliable, and may be compared to a sheet of paper. After having been thus prepared round pieces of the required size are cnt off from it and formed on the lathe by pressure to the shape ot' a cap, as shown in Figs. l, 2, and 4, as above mentioned. When the required shape has been obtained, and the cap being still on the lathes mandrel, running at great Vvey the steam within the cap A.

speed, the flat-bottomed part of the cap is strongly pressed upon with a round steel tool. By this pressure the iiattened bottom acquires a great rigidity, although remaining very pliable. The silver sheet is in the internal part of the cap; but the cap could be formed by a copper sheet between two silver sheets. The cap thus obtained isvthe most important piece of my gage. It is adjusted in a hollow brass screw, a a b b, shaped for the purpose. ln order to have these two pieces strongly united together the lower part of the cap A is previously dipped in a melted tin or silver bath, and the upper inner part ot' the screw a b is also tinned over. Then both pieces, being introduced inlone another, are submitted to heat, so as to have them strongly and tightlyjoined together. When cool, the cap and screw form but one piece. This joint is merely a soldering, which is entirely a new mode ot` making joints. Hitherto the joints ot steam-gages were flat, which caused the escape of steam or gas, and besides were both difficult and costly7 to make. This joint has another great advantage which is not to be found in any other, viz., the soldering is not liable to be impregned to by the fluid pressing in the cap, since it is outside ot' the said cap. Then the pressing uid can cause no damage, since it only touches the silver covering, which cannot be affected by it, and the joint is out ot' its reach.

The screw in which the cap A is fitted is composed of two parts, the top or head a a and stem b b, which stem is tapped .outside and put through the lower part ot' the gagebox c c, the head a bearing on the inside of the box, and a nut, d d, engaged on the screw b, sqneezes the head ofthe screw in its place, so that the screw bearing the cap A is bound to the box c. The screw b is lower and fitted into the screw-nut e, which holds the hanged tube c c', with which is soldered the tube conveying the steam or gas which exerts a pressure. The screw b is hollow, as shown, corresponding with the hole of the tube c to con- This cap being very pliable, its upper part, a, yields, becoming convex as soon as the fluid exerts a pressure within. This pressure is exerted in all directions, as shown by arrows 5 but on account ot the very shape of the cap the pressure takes place without tearing o r exhausting the cap, since the pressure tending to throw it u p is partly balanced by the pressure against the sides of the head a a and by the solder of the cap in its seat.

Over the upper part of the cap Als a small button, j'. 'l It is lens-shaped at its lower side,

and bears at its upper side a small screwtapped rod, which crosses freely through the spring g g g. (Shown alonein Fig. 8.) A small nut, g, is put on the tapped rod, to hold those two pieces fast together. The end of the screwtapped rod is notched, and the end of a small steel connecting-rod, 7L, entering this notch, is attached to it by a small pin for hin ging. The other end of the connecting-rod his forked, as shown in Fig. 3. A neck, 7L', ofasmall crankshaft, z', Figs. 2, 7, and 14, enters into the forked end of the connecting-rod h. The shaft imoves the hand k, showing the degrees of pressure on a dial. The cranked shaft 'i runs on one side on a small support. On the other side, atj, Fig. 7, it runs in a hole of the deck 17%", Figs. 5, 6, and 14:. The lengthened shaft j crosses the dialj, to be tted outside with the hand 7c. The cranked sh afti bears atits lower side a small ring, 7c', kept fast on it, Figs. 1, 2, and 14, which ring is pierced through to enter the end of a thin steel or brass wire, Z. The other end of this wire enters in a hole of the deck t fi, Figs. 5 and 6, where it is strongly held, while the other end can move in the ring k. The effect of this wire, which is slightly twisted, is to bring the hand back when the connecting-rod h moves down or when the pressure lessens, because the connecting-rod, being forked and open above, can work upward only, while the twisted wire Z performs the rods duty when the latter moves down. The action of this unbending or untwisting wire is the same as that used to close the open doors. The combined action of these two pieces is new in mechanical purposes. The bearing t is also provided with two small pins, m m', (shown in Figs. 1 and 2,) against which the ring 7c can hit. The object of the said pins is to stop the cranked shaft, and to prevent it to revert to its motion when arriving at the lower deadpoiut, being actuated by the wire working as a spring.

The application of the steel spring g g is of very great importance in theconstruction of my improved steam-gages. This spring is formed, by preference, of a steel blade, and can be made of any other suitable metal. This blade is bent so as to have its two ends coming near each other, as shown in Figs. l, S, and 25. They are attached by screws to the chair o o, Figs. 1, 10, and 11. The spring g g, being left free, is so formed that it does not tend to unbend or lose its shape. This form is very advantageous, because, when -the pressure ofthe steam forced into the cap A is conveyed to the spring g g by means of the lensshaped piece j', the former is depressed according to the degree of pressure; but, unlike any other spring used in steam-gages, the alteration of shape takes place without any friction or fatigue, which can easily be understood,

since the immovable point of the spring is at B and the pressure is applied at C, at the other end of the diameter. The modification of shape and motion of the spring takes place as shown by arrows-wiz., on free points, where no other resistance but that of the springis to be found. The length of this spring is about eight inches. Now, to work the hand for the whole wayit is to travel on the dial, the cap A and spring have to move at most but one-'twenty-iifth of an inch. and consequently the alteration in the spring is the one two-hundredth part of its whole length. The length of this spring is very advantageous for the most important end for which steam-gages are used.

The s )rings hitherto used were too short and' both ends were tightly fastened. If not, they were subject to strong friction as they moved, which soon spoils them, wears them out, and presents, wrong indications of the degrees of pressure.

The fitting of the dial-glass and box are the same as in those used for similar purposes.

l will now describe how the apparatus works.

The duid passing into the cap A causes the upper side, a a', of the said cap to swell up. This swelling up causes the touching pieces j" to move up, and, of course, the spring is depressed. The spring gg gives the measure of the pressure, and as this organ is in an unchangeable condition and always gives true indications, these indicationsr we can safely rely on. The cap, as already stated, is very pliable, and is only used for transferring or conveying the pressure to the spring without suffering any space to be lost, and the spring transfers the same over to the dial by the help ofthe hand. By the pressure transferred to the spring it is depressed alittle. The end of the little tapped rod moves up the same length, raising up the small forked connecting-rod h, which a-ctuates the cranked shaft conveying the hand, and the latter points out onthedial the corresponding pressure. As soon as the pressure decreases the swelling up of the cap recedes and the spring unbends the corresponding quantity. The piece f, resting on the cap and the connecting-rod, followsthemotion. Theforked shaft, being no longer acted upon by the forked rod la, untwists and brings back the hand to show the depression of the fluid on the dial. `When the pressure increases anew the cap swells up again and the reverted motion of the hand takes place. 1t will be easily understood that whenever the pressure increases or decreases the same motions of the pieces are performed in the same manner, and the exact state of the pressure of the huid will always be correctly shown on the dial.

My improved steam gage being now described with reference to the ligures above mentioned, I will now enumerate all the said figures in the annexed drawings.

Fig. 1 is the inside front view of the steamgage, the dial of which being taken out, the whole inside part can be plainly seen. Fig. 2 is a vertical section of the same through the line X Y. Fig. 3 is the forked connectingrod. Fig. 4 is the pliable metallic cap. Figs. 5 and 6 are the hand-bearing deck; Fig. 7,the cranked shaft; Fig. 8, the spring 5 Fig. 9, the lens-shaped piece resting over the cap; Figs. 10 and 11, the chair or seat to which the spring is attached; Figs. 12 and 13, the hand. Fig. 14 shows the fitting and arrangement of the cranked shaft, twisting-wire, deck, and hand. Fig. 15 is an exterior front view of the steamgage ready to work. Fig. 25 is a front view of a steam-gage somewhat differently disposed from the rst by the mode of actuating the hand for the purpose of obtaining circular divisions around the dial.

The connecting-rodi) (shownin Figs. 12,19, and 25) is not forked, but hinged atqbetween two small projecting plates at the lower part of the toothed sector r, as shown in Figs. 20, 21, 22, 23, and 25. The said sector cogs with a pinion tted on the hands shaft at the center of the gage. The deck carries two bearings for the axles of the hand and sector to run inthe said deck or chair, which is attached to the bottom of the gage with screws. When the connecting-rod p is moved up or down, by the swelling or shrinking of the cap, the sector is actuated, and causes the pinion to move round, and, of course, the hand carried by the axle of the pinion partakes of this motion, showing the degrees of pressure over the dial. A thin spiral spring wound up round the axle of the pinion causes its teeth, to bear constantly on the sectors teeth to insure their regular combined movement and prevent their wabblin g.

Fig. 24 shows a similar disposition with y some diierence in the connecting-rod, which hangs from the upper part of the piece t. The foot of the rod t (shown in Figs. 16, 17, and 24) forms a nut to take the place of the one shown in Figs. l and 2. The connectingrod u, hinging at t' at its upper end, hangs down, entering between two small plates at the bottom of the sector. The motion is communicated to the hand as in Fig. 25. The chairs or decks for this last arrangement are shown in Figs. 26 and 27.

Fig. 28 shows another shaped cap a little different from the rst. Its upper side is undulated, which allows a greater swelling up.

Figs. 29 and 3() show another disposition of a steam-gage, in which the fitting of the cap and spring is different from those before described. The cap A is carried by a piece, E, shaped for the purpose. A second piece or ring, F, is placed inside. Both pieces E and F are grooved at V. Some melted tin or silver 1s introduced into this groove, to form a joint that will bind both pieces rmly together as soon as the metal cools. The steam ingresses through V and fills up the cap, swelling it higher. The pressure is transmitted to the double-bowed spring x mby the button V. The up motion of the lower spring is conveyed to the hand 00 through the medium of the connecting-rod x', which hinges at x on the side of the hand. The ends of the blades of Athe spring are attached together by small bolts. chair.

Fig. 31 shows another kind of spring, having a circular shape. One of its ends is attached to the case of the gage. The other end, being free, bears on the rod of the button or lens-piece and actuates the connecting-rod.

Fig. 32 shows a round-shaped spring, of which both ends are fastened up to the case of the gage, while the lower part is actuated by the pressure of the steam through the cap.

Fig. 33 shows another disposition, composed of two spiral springs, H H', the outer ends of which are attached to the rod of the button resting on the cap. This rod is guided by the guide-piece Z.

My invention being now described, together with the arrangements, ttings, and the work of all its organs of this improved steam-gage, I wish to observe that I do not confine myself to the precise minute details which are represented in the annexed sheet of drawings, so long as the principal distinctive character o the invention is retained; but

I claim- The axle of the hand is carried by the 1. The metallic cap A, constructed and arranged substantially as and for the purposes described.

2. The joint of said cap, by which it is securely affixed to its seat, so as to prevent its being torn away therefrom by the internal pressure of the steam, as specified.

3. The spring g, constructed and arranged as herein described, 'whereby to prevent the friction, wear, and tiring thereof, so that the pressure of the steam shall be thereby constantly and correctly indicated.

et. The combination and arrangement of the connecting-rod h, crank fi, and spring lto regulate the mot-ion of the hand 7c, as above set forth.

5. The several parts of the steam-gage included in the above-enumerated claims and their connections combined, substantially as and for the purposes specified.

J. J. DUCOMET.

Witnesses:

JAQUEs DUCAMP, VICTOR PRINCE. 

